Drying plant



Q Dec. 4 1923. I

o. NORDSTRM DRYING LAnT Filed July '7, 1922 2 Sheets-$heat 1 o. NORDSTR O M DRYING PLANT Filed July 7 i922 2 Sheets-Shut l iatented Dec. 4, 1923.

' "UNITED STTES or'ro nonns'rnorr, or

SUNDSVALL, SWEDEN.

' Dianne rLAnr,

' Application filed July 7 1922. Serial No. 5733428.

To all whom it may concern:

Be it known that I, G'r'ro NoRosrRoM, a citizen of the Kingdom of Swedemresidmg a new and useful Improvements in Drying Plants of which the following is a specification. p

This invention relates to drying plants comprising one or more drying towers'each including an annular drying chamber having perforated walls, and'in which the material to be dried descends through said annular chamber, hot gases or hot air being at the same time passed through said chamber, preferably by means of a fan-blower pressing the gases into the central space within the wall of said chamber from which space the gases will then pass through the apertures of the said inner Wall and into the annular drying chamber and will there upon escape through the apertures formed in the outer wall of the drying chamber.

The object of this invention is to provide means to automatically maintain the temperature of the gases entering the drying chamber at a constant height or to adjust same according to the degree of moisture of the material to be dried. The apparatus used for obtaining this purpose will appear from the following specification when taken in consideration with the accompanying drawing in which:

Figure 1 is a diagrammatic vertical section of a drying plant constructed according to this invention.

Figure 2 is a view on an enlarged scale illustrating the preferred form of thermoresponsive .device employed with the. invention.

In the drawing. the numeral 1 indicates the perforated cylindrical inner wall of a drying tower of well-known design. 2 is the outer likewise perforated wall of said drying tower- The annular space formed between said two walls is adapted to serve as a drying chamber. To this end an elevator 3 is provided serving to feed the material to be dried into the said chamber at the top thereof. Provided at the bottom of the drying chamber is a feed out or emptying de: vice 41/ The whole structure is surrounded by a casing 5, preferably consisting of brick work, surrounded by a chimney 6. In the interior of the inner cylindrical wall 1 the hot drying gases are introduced through a conduit 7 from a'famblower 8 to the inlet 'end of which a Sundsvall, Sweden, have invented devices. describe Accord ngto this invention I havenow provided a pipe-line 18 of arrestricted cross '(pipe 9 isconnected v The section area between. the conduits. 7 and 9 asfa shunt to the fan-blower Inserted in said pipe-line 18 man adgusting device responsive to a definite temperature," to control 'a 'damper 19 mounted in a conduitrl0ieiztending from the inlet pipe. 90f thefan-b-lowe r 8 to the space 11 formed between the outer wall 2 of the drying tower and the casing Said thermoresponsive device is only indiit is well-known per se.

" It is well understood that a gas current having the same temperature as that of the gases entering the drying tower, will always circulate in the direction of the arrow through the pipe line 18. As the temperature rises above that for which the thermo responsive device 20 is adjustech'said device will open the damper 19 to permit comparatively cool gases to passfrona the space 11 and to the fan-blower 8 to. dilute the .hot gases entering through the conduit 9 until the temperature of the gases when leaving the fan-blower has sunken in the desired degree.

The diluting gases are taken from the space 11 in order that no amount of heat may be consumed in heating a quantity of fresh air that would otherwise be required. and to maintain the amount of carbonic acid contained in the drying gases as high as possible.

Many types of thermo-responsive devices are known, which may be used for the having a large coeflicient of expansion due to heat. Said pipe 21 isclosed at its one end by a bellows 22 the bottom of which carries a pin 23 on which one arm of a double armed lever 24 pivoted at '25 freely rests. The one the damper 19, the other end of the leyer 24 carrying a counter weight 28. The p1pe'21 end of said lever 2 1 is connected by a link 26 to a crank arm. 27 on the shaft of is inserted inthe pipe-line 18 so that the eX- pension and contraction of the liquid within the pipe 21 will be controlled by the heat of the gas flowingthrough: pipe-line 18.] As 7 the said liquid expands or contracts" it will which will in turn gcontrolthe damper 191 7 What I claim is g V 1. In a drying plant, the combination With a drying tower, comprisinga drying chamber to be passed through by the mapassed by the drying gases after their pas terial to be dried as Well as by hot' dryi'ng gases, and further comprisinga space to be sage through the drying chamber, of means for causing'the hot gases to enter the drying chamber, a connection extendin'gbetween 7 said means, a throttling. member inserted in i said last-mentioned space and the vinlet of said connection, and an adjusting deviceto control said throttling 'member according to'the temperatureof the gases when leaving a the said means.

., [2. In afidrying plant,

with a drying tower, comprising a drying the combination chamber to be-passed through by the ma I terial to be-dried as We1l asbyh0t drying gases, and further comprising aspace to be passed by the drying gases after their pas sage throi'i'gh the drying chamber, ofmeans for causing the hot gase to enter the drying chamber, a connection extending between isaid last-mentioned space and the inlet of said means, a throttling member inserted in said connectiom a, pipe-1ine arrangedtas ja shunt'to the said means between: the inlet and the outlet .thereof;, and w an adjustin v fdevice inserted in saidpipe-line t0 contr 7 said throttling member according; to the temperaturevof theigases when leaving the said means; 7

' i em 'noRns rRo In testimony whe e f I hi i f namefi- 

